The Universal Tube Output Stage can be connected and configured in many different configurations to allow for virtually all DAC’s made to be connected correctly.
In order to select the correct input wiring and jumper setting you need to determine the actual part number of the DAC Chip fitted to your CD-Player, DVD-Player or DA-Converter. If your DAC Chip is listed in the Appendix you only need to select the correct page for this DAC.
You will still need to determine the actual Pins on the DAC Chip that carry the output signal, analogue ground and if present reference voltage. You will need to tap off these DAC Chip pins and connect them to the Universal Tube Output Stage.
If the DAC Chip has a so-called “voltage” output you can keep the original solid state analogue stage connected and run it and the Universal Tube Output Stage in parallel.
If the DAC Chip has a so-called “current” output you must disconnect the original solid state analogue stage from the DAC. This usually means cutting away the traces connecting to the current output pins.
As can be seen from the above, one of the key distinguishing marks of DAC Chips for our application is the presence of Voltage or Current outputs. Usually current outputs tend to sound better as there is no additional circuitry build into the DAC Chip to convert the current from the actual DAC into Voltage. Some DAC Chips have the circuitry for current to voltage conversion on chip, but allow the user to access the current output. In this case using the current output is preferred.
Other items of concern when selecting the correct connection and settings are if the DAC Outputs actually are referenced to Analogue Ground (0V DC on the DAC output pins) or if they are referenced to a so-called “reference voltage” (around 2.5V DC offset on the DAC output pins).
Of final concern is if the DAC used has single ended or balanced outputs. If the DAC has only Single Ended outputs it is not possible to get a balanced output signal.
Conversely, DAC’s that have a balanced output can generally be connected in single ended mode with little or no complications.
In the following we will cover individual configurations for various DAC Chip Structures.
Wherever possible a list of known DAC’s conforming to this scheme is given.
Known means they are known to have been manufactured at some time and are documented in the public domain to have technical data and design features placing them into the group of DAC’s using this scheme. It does not imply that the particular combination of DAC and Universal Tube Output Stage has been tested with this type of DAC.